1. Field of the Invention
The invention relates to a plastic housing, which can be subjected to internal pressure, comprising an upper housing part, a lower housing part, and a closure that connects both housing parts to one another.
2. Description of the Background Art
German Offenlegungsschrift No. DE 102 38 416 A1 or German Utility Model No. DE 20 2005 017 576 U1 discloses fluid flow meters, which have a pressure-resistant plastic housing. The housing has an upper housing part and a lower housing part. Both have a circumferential, outwardly positioned flange. A two-part locking ring, overlapping both flanges and thereby connecting the housing parts to one another, has a U-shaped cross section and connects the upper housing part and lower housing part together in a tension-resistant manner.
Experience has shown that this construction has two basic weak points. The first weak point is the inner edge between the respective housing parts and its flange; the second weak point is the sharp inner edge between the locking ring base and the locking ring side wall. Because of the leverage effect under the influence of high internal pressure forces in the housing, bending moments occur, which can lead to crack formation and thereby to failure, when this is not prevented by appropriate oversizing of the wall thicknesses and the transition radii. This is unsatisfactory.